Pollak's feature breakthrough came when Barry Levinson cast him as Aidan Quinn's business partner in "Avalon" (1990). Casting agents and directors soon realized his potential and several intriguing roles followed, most notably playing Steve Martin's unscrupulous agent who sleeps with his girlfriend in "L.A. Story" (1991) and a breakout success as part of the defense team alongside Tom Cruise and Demi Moore in the military courtroom drama "A Few Good Men" (1992). Under Rob Reiner's direction in the latter, he drew substantial praise for his subtle portrayal of legal assistant Lieutenant Sam Weinberg, Reiner had in fact, previously tapped the actor to headline the CBS summer sitcom "Morton & Hayes" (1991), in which he was teamed with Bob Amaral as forgotten clowns of the 1930s and 40s (in the vein of Laurel and Hardy or Abbott and Costello), The novelty of the series (each week featured another lost black and white short featuring the duo) was perhaps too esoteric for audiences seeking escapist fare.
While his turn as Walter Matthau's son (and Darryl Hannah's love interest) in "Grumpy Old Men" (1993) offered good exposure, Pollak hit his stride as a character actor in 1995. He lent his flair for comedy to the role of an unfaithful husband in "Miami Rhapsody" and then demonstrated his dramatic mettle as the "soulless bastard" among "The Usual Suspects" and an innocent front man in Martin Scorsese's "Casino" (both 1995). The uneven comedy "House Arrest" (1996), which teamed him with Jamie Lee Curtis, inaugurated a string of less than successful features, including the hostage drama "Truth or Consequences, N.M." (1997), the low-budget crime melodrama "Outside Ozona" (1998) and the apocalyptic Schwarzennegger vehicle "End of Days" (1999), in which he was arguably the best thing as Arnold's sardonic sidekick. When critic-turned-filmmaker (and poker buddy) Rod Lurie offered him the role of US President, Pollak could not refuse. He delivered a persuasive performance as the Chief Executive confronting a world crisis from the confines of a snowbound diner in the 1999 festival-screened thriller "Deterrence". It was back to comic form the following year as Hungarian gangster Janni Pytor Gogolak (replete with a Gabor-like accent) in "The Whole Nine Yards"—he returned playing (in heavy makeup) his character's ancient father Lazlo Gogolak in the 2004 sequel "The Whole Ten Yards."
He then portrayed attorney Gerry Lefcourt in the Abbie Hoffman indie biopic "Steal This Movie!" (2000) and began specializing in strategic supporting turns and cameos in a series of studio comedies, including "The Wedding Planner" (2001), "3,000 Miles to Graceland" (2001), "Juwanna Man" (2002), as an unlikely god of love Cupid in "The Santa Claus 2" and in the family holiday film "Blizzard" (2003). Pollack could be seen both in character on the big screen as a rabbi in "Stolen Summer" (2002), and behind the scenes as himself on the first season of the HBO docu-series "Project Greenlight," which chronicled the making of that film. Pollack's distinctive delivery could be heard when he lent his vocal talents to an alligator in the Eddie Murphy remake-cum-sequel "Dr. Doolittle 2" (2001), and in the all-star cast of the aquatic, GCI-animated "Shark's Tale" (2004). He next appeared as a shady accountant possessing a disc of damning digital information in “Hostage” (2005), a cliché-ridden thriller starring one-time action hero Bruce Willis as a former hostage negotiator turned small town police officer.